Sleeping posture could affect brain health

Sleeping on your side rather than your back or stomach might play a role in helping reduce your risk of developing Alzheimer's and other neurological diseases, according to a new study.

06.08.2015

(AFP) Sleeping on your side rather than your back or stomach might play
a role in helping reduce your risk of developing Alzheimer's and other
neurological diseases, according to a new study.

Side sleeping opens a passage in the brain called the glymphatic
pathway that dispels waste and other chemicals, say the researchers from
Stony Brook University in the US.

"It is interesting that the lateral sleep position is already the
most popular in human and most animals, even in the wild, and it
appears that we have adapted the lateral sleep position to most
efficiently clear our brain of the metabolic waste products that built
up while we are awake," says Dr. Maiken Nedergaard of the University of
Rochester.

The team's research began years ago when they used magnetic resonance
imaging (MRI) technology to observe the glymphatic pathway in rodents.

They learned that the waste-clearing process, bathing the brain
with cleansing cerebrospinal fluids (CSF) and interstitial fluid (ISF), is most efficient during sleep.

What gets flushed out the glymphatic pathway are amyloid β and tau proteins that are unhealthy in the brain if they build up.

In the study, lead author Dr. Helene Benveniste and her team used MRI
technology and kinetic modeling to measure the exchange rates of the
fluids CSF and ISF in rodents who had been given anesthesia as they
slept on their sides, backs and stomachs.

Sure enough, technologies called fluorescence microscopy and
radioactive tracing that gave the team a view of the glymphatic pathway
revealed increased efficiency when the rodents slept on their sides.

Dr. Nedergaard says the results of the study serve as further proof that sleep serves a waste-eliminating function.

"Many types of dementia are linked to sleep disturbances, including
difficulties in falling asleep," she says, suggesting that such
disorders may be linked in some way to brain waste not being properly
eliminated. "It is increasingly acknowledged that these sleep
disturbances may accelerate memory loss in Alzheimer's disease."

Body posture and sleep quality should be assessed in humans as the
scientific community begins to lay the groundwork for further research
that could enrich our knowledge of these brain diseases, says Dr.
Benveniste.

She cautions individuals that the team's research was conducted on
rodents and that further experimentation will be needed to determine
whether or not their conclusion applies to humans.